The march, planned in defiance of a ban by city authorities, risks provoking police crackdown on protestors.

“There is a greater danger of the excess application of police force if the march takes place,” said veteran rights campaigner Lyudmila Alekseeva, head of the Moscow Helsinki group.

Authorities’ treatment of an opposition demonstration ahead of presidential elections in March, which saw over 100 activists arrested, drew international condemnation.

Interior ministry official Vladimir Pronin warned Moscovites to stay home Tuesday: “I categorically counsel you not to break the law in Moscow and moreover, I recommend you to stay away from those demonstrations that have provocation as their aim.”

“Today’s plans are a provocation,” Pronin was quoted by Interfax as saying.

Human rights monitors, including lawyers, will monitor the march in case of altercations with the police, prominent human rights leader Lev Ponomarev told Ekho Moskvy radio ahead of the March Tuesday.

“If the police will flex their power, nobody can protect the people,” said Ponomarev.

A request submitted by Kasparov and fellow opposition leader Eduard Limonov, head of the unregistered National Bolshevik Party, for the march on April 21 was turned down.

City officials said the space had already been reserved for a meeting of a pro-Kremlin youth group.

But Kasparov, who has been sidelined from state politics, has said all protest would go on despite authorities’ threats, promising a fight to the end. DPA